javafx.animation

Class Interpolator

java.lang.Object

javafx.animation.Interpolator

public abstract class Interpolator
extends java.lang.Object

The abstract class defines several interpolate methods, which are used to calculate interpolated values. Various built-in implementations of this class are offered. Applications may choose to implement their own Interpolator to get custom interpolation behavior.

A custom Interpolator has to be defined in terms of a " curve()".

Since:

JavaFX 2.0

Field Summary

Fields

Modifier and Type	Field and Description
static Interpolator	DISCRETE Built-in interpolator that provides discrete time interpolation.
static Interpolator	EASE_BOTH Built-in interpolator instance that provides ease in/out behavior.
static Interpolator	EASE_IN Built-in interpolator instance that provides ease in behavior.
static Interpolator	EASE_OUT Built-in interpolator instance that provides ease out behavior.
private static double	EPSILON
static Interpolator	LINEAR Built-in interpolator that provides linear time interpolation.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Interpolator() The constructor of Interpolator.

Method Summary

Modifier and Type	Method and Description
private static double	clamp(double t)
protected abstract double	curve(double t) Mapping from [0.0..1.0] to itself.
boolean	interpolate(boolean startValue, boolean endValue, double fraction) This method takes two boolean values along with a fraction between 0.0 and 1.0 and returns the interpolated value.
double	interpolate(double startValue, double endValue, double fraction) This method takes two double values along with a fraction between 0.0 and 1.0 and returns the interpolated value.
int	interpolate(int startValue, int endValue, double fraction) This method takes two int values along with a fraction between 0.0 and 1.0 and returns the interpolated value.
long	interpolate(long startValue, long endValue, double fraction) This method takes two int values along with a fraction between 0.0 and 1.0 and returns the interpolated value.
java.lang.Object	interpolate(java.lang.Object startValue, java.lang.Object endValue, double fraction) This method takes two Objects along with a fraction between 0.0 and 1.0 and returns the interpolated value.
static Interpolator	SPLINE(double x1, double y1, double x2, double y2) Creates an Interpolator, which curve() is shaped using the spline control points defined by (x1, y1 ) and (x2, y2).
static Interpolator	TANGENT(Duration t, double v) Creates a tangent interpolator, for which in-tangent and out-tangent are identical.
static Interpolator	TANGENT(Duration t1, double v1, Duration t2, double v2) Create a tangent interpolator.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EPSILON

private static final double EPSILON

See Also:

Constant Field Values

DISCRETE

public static final Interpolator DISCRETE

Built-in interpolator that provides discrete time interpolation. The return value of interpolate() is endValue only when the input fraction is 1.0, and startValue otherwise.

LINEAR

public static final Interpolator LINEAR

Built-in interpolator that provides linear time interpolation. The return value of interpolate() is startValue + (endValue - startValue) * fraction.

EASE_BOTH

public static final Interpolator EASE_BOTH

Built-in interpolator instance that provides ease in/out behavior.

An ease-both interpolator will make an animation start slow, then accelerate and slow down again towards the end, all in a smooth manner.

The implementation uses the algorithm for easing defined in SMIL 3.0 with an acceleration and deceleration factor of 0.2, respectively.

EASE_IN

public static final Interpolator EASE_IN

Built-in interpolator instance that provides ease in behavior.

An ease-in interpolator will make an animation start slow and then accelerate smoothly.

The implementation uses the algorithm for easing defined in SMIL 3.0 with an acceleration factor of 0.2.

EASE_OUT

public static final Interpolator EASE_OUT

Built-in interpolator instance that provides ease out behavior.

An ease-out interpolator will make an animation slow down toward the end smoothly.

The implementation uses the algorithm for easing defined in SMIL 3.0 with an deceleration factor of 0.2.

Constructor Detail

Interpolator

protected Interpolator()

The constructor of Interpolator.

Method Detail

SPLINE

public static Interpolator SPLINE(double x1,
                                  double y1,
                                  double x2,
                                  double y2)

Creates an Interpolator, which curve() is shaped using the spline control points defined by (x1, y1 ) and (x2, y2). The anchor points of the spline are implicitly defined as (0.0, 0.0) and (1.0, 1.0).

Parameters:

x1 - x coordinate of the first control point

y1 - y coordinate of the first control point

x2 - x coordinate of the second control point

y2 - y coordinate of the second control point

Returns:

A spline interpolator

TANGENT

public static Interpolator TANGENT(Duration t1,
                                   double v1,
                                   Duration t2,
                                   double v2)

Create a tangent interpolator. A tangent interpolator allows to define the behavior of an animation curve very precisely by defining the tangents close to a key frame. A tangent interpolator defines the behavior to the left and to the right of a key frame, therefore it is only useful within a Timeline. If used in a KeyFrame after a KeyFrame that has different interpolator, it's treated as if the out-tangent of that KeyFrame was equal to the value in the KeyFrame.

The parameters define the tangent of the animation curve for the in tangent (before a key frame) and out tangent (after a key frame). Each tangent is specified with a pair, the distance to the key frame and the value of the tangent at this moment.

The interpolation then follows a bezier curve, with 2 control points defined by the specified tangent and positioned at 1/3 of the duration before the second KeyFrame or after the first KeyFrame. See the picture above.

Parameters:

t1 - The delta time of the in-tangent, relative to the KeyFrame

v1 - The value of the in-tangent

t2 - The delta time of the out-tangent, relative to the KeyFrame

v2 - The value of the out-tangent

Returns:

the new tangent interpolator

TANGENT

public static Interpolator TANGENT(Duration t,
                                   double v)

Creates a tangent interpolator, for which in-tangent and out-tangent are identical. This is especially useful for the first and the last key frame of a Timeline, because for these key frames only one tangent is used.

Parameters:

t - The delta time of the tangent

v - The value of the tangent

Returns:

the new Tangent interpolator

See Also:

TANGENT(Duration, double, Duration, double)

interpolate

public java.lang.Object interpolate(java.lang.Object startValue,
                                    java.lang.Object endValue,
                                    double fraction)

This method takes two Objects along with a fraction between 0.0 and 1.0 and returns the interpolated value.

If both Objects implement Number, their values are interpolated. If startValue implements Interpolatable the calculation defined in interpolate() is used. If neither of these conditions are met, a discrete interpolation is used, i.e. endValue is returned if and only if fraction is 1.0, otherwise startValue is returned.

Before calculating the interpolated value, the fraction is altered according to the function defined in curve().

Parameters:

startValue - start value

endValue - end value

fraction - a value between 0.0 and 1.0

Returns:

interpolated value

interpolate

public boolean interpolate(boolean startValue,
                           boolean endValue,
                           double fraction)

This method takes two boolean values along with a fraction between 0.0 and 1.0 and returns the interpolated value.

Before calculating the interpolated value, the fraction is altered according to the function defined in curve().

Parameters:

startValue - the first data point

endValue - the second data point

fraction - the fraction in [0.0...1.0]

Returns:

the interpolated value

interpolate

public double interpolate(double startValue,
                          double endValue,
                          double fraction)

This method takes two double values along with a fraction between 0.0 and 1.0 and returns the interpolated value.

Before calculating the interpolated value, the fraction is altered according to the function defined in curve().

Parameters:

startValue - the first data point

endValue - the second data point

fraction - the fraction in [0.0...1.0]

Returns:

the interpolated value

interpolate

public int interpolate(int startValue,
                       int endValue,
                       double fraction)

This method takes two int values along with a fraction between 0.0 and 1.0 and returns the interpolated value.

Before calculating the interpolated value, the fraction is altered according to the function defined in curve().

Parameters:

startValue - the first data point

endValue - the second data point

fraction - the fraction in [0.0...1.0]

Returns:

the interpolated value

interpolate

public long interpolate(long startValue,
                        long endValue,
                        double fraction)

This method takes two int values along with a fraction between 0.0 and 1.0 and returns the interpolated value.

Before calculating the interpolated value, the fraction is altered according to the function defined in curve().

Parameters:

startValue - the first data point

endValue - the second data point

fraction - the fraction in [0.0...1.0]

Returns:

the interpolated value

clamp

private static double clamp(double t)

curve

protected abstract double curve(double t)

Mapping from [0.0..1.0] to itself.

Parameters:

t - time, but normalized to the range [0.0..1.0], where 0.0 is the start of the current interval, while 1.0 is the end of the current interval. Usually a function that increases monotonically.

Returns:

the curved value